PROBLEM TO BE SOLVED: To provide a biological information acquiring device or the like the power source state of which can be surely changed to a desired one.SOLUTION: This biological information acquiring device includes a biological information acquiring part capable of acquiring biological information, and also includes: a power source which can supply electric power for driving the biological information acquiring part a power supply control part which takes control for conducting or blocking power supply to the biological information acquiring part from the power source a control signal detection part which outputs a detection signal when detecting at least one of a primary control signal for starting the biological information acquiring device and a secondary control signal for stopping the biological information acquiring device and a state-switching control part which maintains the controlled condition of the power supply control part when one control signal detected last time is detected again this time, and changes the control condition of the power supply control part when another control signal different from the one control signal is detected this time, based on the output condition of the detection signal from the control signal detection part.
